Let us first start with the most beautiful thing you mentioned, that you acknowledge the power of Jesus' name. It is only in His name that we can come before God the Father with our petitions.
We join with you in praying for your spouse, asking God to grant him complete healing according to His will. We trust in the Lord's promise, For I know the thoughts that I think toward you, says Yahweh, thoughts of peace, and not of evil, to give you hope and a future (WEB, Jeremiah 29:11). We plead the blood of Jesus over your spouse's life, praying for his health to be restored and for both of you to enjoy a long, blessed, and happy life together.
We also take this opportunity to remind you of the precious promise in Romans 10:9, that if you will confess with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved. And in James 4:14-15, we are reminded that our life is but a vapor. We are encouraged to say, If the Lord wills, we will live, and do this or that and in 2 Corinthians 5:8, we are told that to be absent from the body is to be at home with the Lord.
While we pray for long life and happiness, we must also remember that our ultimate hope is in eternal life with Jesus Christ. We encourage you both to continue growing in your faith and love for the Lord, for He is the source of true joy and happiness.
In light of your husband's advanced age, we encourage you to cherish each moment together and to continue building a strong, godly marriage that honors the Lord. Remember the words of Ecclesiastes 9:9, Live joyfully with the wife whom you love all the days of your life of vanity, which he has given you under the sun, all your days of vanity: for that is your portion in life, and in your labor in which you labor under the sun.
We rebuke anything that does not align with biblical principles in your request. We also pray that you both will continue to live for Jesus Christ, forsaking all else.
Father, we come before You in the name of Jesus, lifting up this beloved couple. We ask for Your healing touch upon the husband, restoring his health and granting them many happy years together. Help them to live in Your love and grow in their faith. We ask for Your blessing in Jesus Christ.